1. Field
The present disclosure relates to a carbazole compound and an organic light-emitting device including the same.
2. Description of the Related Art
Organic light-emitting devices (OLEDs) are self-emission devices that have wide viewing angles, high contrast ratios, short response times, and excellent brightness, driving voltage, and response speed characteristics, and produce multicolored images.
A typical organic light-emitting device may include an anode, a cathode, and an organic layer that is disposed between the anode and the cathode and includes an emission layer. In an organic light-emitting device, a hole transport region may be formed between the anode and the emission layer, and an electron transport region may be formed between the emission layer and the cathode. Holes provided from the anode may move toward the emission layer through the hole transport region, and electrons provided from the cathode may move toward the emission layer through the electron transport region. The holes and electrons may be recombined in the emission layer to produce excitons. These excitons may change from an excited state to a ground state, thereby generating light.
In order to improve emission efficiency of the organic light-emitting device, the emission layer may include a host. As a host material, a carbazole compound having hole-transporting capability and a large energy band gap in a triplet state can be used. Particularly, a carbazole compound, such as 4,4′-N,N′-dicarbazole-biphenyl (CBP) or 1,3-bis(carbazole-9-yl)benzene (mCP), is known to be used as a host material of the organic light-emitting device.
JP 2003-335753 A discloses a carbazole compound having electron-transport capability provided by substituents introduced to the N-, 2-, and 3-positions of the carbazole moiety.
However, the carbazole compound including a functional group for electric charge transport introduced to the N-, 2-, and 3-positions of the carbazole moiety as disclosed in JP 2003-335753 A has problems with decreasing energy band gap values in a triplet state.
Thus, there remains a need in a carbazole host having electric charge transporting capability and a large energy band gap in a triplet state to ensure its optimal performance in an organic light-emitting device.